The invention relates to a power tool, particularly a power screwdriver, preferably one having a built-in pneumatic motor, and provided with a turn-on switch, with a threshold-torque-responsive clutch for monitoring the torque being transmitted by the tool, and an automatic turn-off arrangement operative for turning off the drive motor in response to the reaching of the threshold torque, with the motor turn-off arrangement including a locking arrangement so designed as to be responsive to a part of the clutch which shifts in response to the transmission of a certain amount of torque and furthermore being coupled to a push rod connected with an activating device arranged for establishing or interrupting the supply of energy to the motor.
A power tool of the general type in question is disclosed in commonly assigned, copending application Ser. No. 631,187, now U.S. Pat. No. 4,006,785, of Karl Roll et al., filed Nov. 12, 1975 and entitled "POWER TOOL". The entire disclosure of which is incorporated herein by reference, and it meets successfully enough the objects set out for it. However, there are situations where it may be desired that the power tool motor not be automatically turned off when the threshold torque is reached, and that instead the power tool motor continue to run and drive the tool at a still higher torque.